Method and apparatus for controlling welding temperature of wrapping material

Abstract

A hammer ( 14 ) coupled to an ultrasonic vibrator ( 15 ) is actuated to apply vibrations to a wrapping material ( 10 ) with irregularities in composition and thickness so that the wrapping material ( 10 ) can be fusion-bonded with uniform strength. The surface temperature of the wrapping material ( 10 ) measured by an infrared sensor ( 30 ) is sent to a control unit ( 22 ), and a controller ( 23 ) sends a control signal ( 24 ) to a variable-voltage source ( 25 ). The variable-voltage source ( 25 ) controls the amplitude of vibrations of the hammer ( 14 ) by temperature feedback to make uniform the generation of heat in the wrapping material ( 10 ).

What is claimed is:  
     
       1. A method for controlling fusion-bonding temperature of a wrapping material, comprising the steps of: 
       in ultrasonic sealing means comprising a wrapping material ( 10 ) and a sealing hammer ( 14 ) that are in relative motion, an ultrasonic vibrator ( 15 ) which actuates the sealing hammer ( 14 ) and applies an impact to the wrapping material ( 10 ) via said sealing hammer ( 14 ), and an electric circuit ( 20 ) for applying oscillating power to said ultrasonic vibrator ( 15 ),  
       measuring by a non-contact-type temperature sensor ( 30 ), in the vicinity of said sealing hammer ( 14 ), the fusion-bonding temperature of the wrapping material ( 10 ) which is heated by continuous impacts of the sealing hammer ( 14 );  
       sending, to a variable-voltage device ( 25 ) for a power source ( 26 ) for said electric circuit ( 20 ), output signals ( 24 ) corresponding to measured temperatures being successively inputted to a control unit ( 22 ) from the temperature sensor ( 30 ); and  
       controlling, with said variable-voltage device ( 25 ), an amplitude of said moveable hammer ( 14 ) in accordance with said measured temperature value, so as to make uniform the heating temperature of the wrapping material ( 10 ).  
     
     
       2. An apparatus for controlling fusion-bonding temperature of a wrapping material, in which ultrasonic sealing means comprises a wrapping material ( 10 ) and a sealing hammer ( 14 ) that are in relative motion, an ultrasonic vibrator ( 15 ) which actuates the sealing hammer ( 14 ) and applies an impact to the wrapping material ( 10 ) via said sealing hammer ( 14 ), and an electric circuit ( 20 ) for applying oscillating power to said ultrasonic vibrator ( 15 ), said apparatus comprising: 
       a non-contact-type temperature sensor ( 30 ) for measuring, in the vicinity of the sealing hammer ( 14 ), the fusion-bonding temperature of the wrapping material ( 10 ) which is heated by continuous impacts of the sealing hammer ( 14 );  
       a control unit ( 22 ) for continuously computing output signals for control corresponding to the temperature values measured by said temperature sensor ( 30 ); and  
       means for sending output signals ( 24 ) from said control unit ( 22 ) to a variable-voltage device ( 25 ) for a power source ( 26 ) for said electric circuit ( 20 ), and controlling an amplitude of said moveable hammer ( 14 ) with said variable-voltage device ( 25 ), so as to make uniform the heating temperature of the wrapping material ( 10 ).